Coxch



United States Patent DIS- AND POLYAZO DYESTUFFS AND PROCESS OF PREPARATION Philippe Grandjean and Willy Steinemann, Basel, and Walter Wehrli, Riehen, Switzerland, assignors to Sandoz A. G., Basel, Switzerland, a Swiss confederation No Drawing. Application November 16, 1953, Serial No. 392,488

Claims priority, application Switzerland November 21, 1952 12 Claims. (Cl. 260-147) The present invention relates to new azo dyestuffs which are characterized by valuable properties.

The new dyestuffs according to the present invention correspond to the formula wherein each of R1-NH and R2--NH-- stands for the radical of an aromatic amine containing from one to three azo groups, one to four water-solubilizing groups and zero to two of the metal atoms copper and nickel, and wherein R1NI-I and R2NH may be identical, x is hydrogen or halogen and y is hydrogen or lower alkyl.

These new dyestuffs are prepared, according to the present invention, by a process which involves condensing (a) two mols of an aromatic amine, containing one or more azo groups, which may be protected by metal atoms in complex combination, and/ or a group which is capable of azo dyestuff formation or a substituent which is convertible into such a group, or (b) two mols of a mixture of two or more such aromatic amines in any desired proportions, with one mol of a butadiene-1,4-dicarboxylic acid halide or a derivative thereof which is substituted by halogen or alkyl, and then coupling the condensation products, when they contain groups capable of azo dyestuff formation or substitutents convertible into such groups, if desired after conversion of the substituents into groups capable of azo dyestuff formation, with suitable diazo compounds or diazotizing the said condensation products and combining them with suitable azo com ponents, and thereafter carrying out any desired further coupling reactions, the components being so selected in this connection that a sufficient number of water-solubiliZing groups are present in the final dyestuffs, and if R'-NH--CO--CH=CH-CH=CH-CO-NH-R wherein the butadiene radical may be substituted by halogen or alkyl, and each RNH- stands for the same radical of an aromatic amine which contains at least one azo group and a sufficient number of water-solubilizing groups to assure water-solubility to the final dyestuff.

On the other hand, when two mols of a mixture, in any desired proportions, of two or more different aro- 2,734,053 Patented Feb. 7, 1956 ice unsymmetrical product, which contains the two starting materials and corresponds to the formula wherein the butadiene radical may be substituted by halogen or alkyl, and the two R-NH- moieties are different radicals of aromatic amines which contain at least one azo group and a sufficient number of watersolubilizing groups to assure water-solubility to the end dyestuffs. The proportion of the three dyestuffs in the final product changes when the mol proportion of the starting materials is changed from 1:1 or when more than two starting substances are used. By selecting the starting materials and the mol proportions in which they are employed, end products with outstanding properties with regard to solubility in water, solubility in the dyebath, fastness to light and fastness to wet treatments are obtained. The optimum properties can advantageously be determined, as regards any particular starting materials by a series of tests with systematically changed mol proportions. It has been found that dyestuff mixtures, obtained from a mixture of starting materials, generally have the same dyeing properties as the homogeneous dyestuffs.

By amines which contain azo groups protected by metal atoms in complex combination, are meant the metal complex compounds of aminoazo dyestuffs which contain for example one or more ortho, ortho'-dihydroxor ortho-hydroxy-ortho'-alkoxyor -carboxy-azo grouping. The metals in complex combination are preferably copper or nickel.

'It is possible, within the scope of the foregoing to combine the butadiene-l,4-dicarboxyl acids with amines or aminoazo compounds which, in addition to the amino group to be condensed also contain a group capable of azo dyestufl. formation or a substituent which is convertible into such a group, and to carry out further coupling reactions with the condensation products obtained with such amines or aminoazo compounds. Groups of this character which are capable of azo dyestuff formation or substituents which are convertible into such groups are for example the couplable CH group and substituents which are convertible into diazotizable amino groups such as the nitro group or a readily saponifiable acylamino group.

In preparing the dyestuffs according to the invention, the starting materialspreferably in the form of the alkali salts--are dissolved in water, and then the butadiene-1,4-dicarboxylic acid halide, which may be dissolved in a solvent such for example as carbon tetrachloride, chloroform, chlorobenzene, methylbenzene or 1,2-dichlorobenzene, is slowly added while stirring thoroughly. The quantity of alkali necessary for neutralization of the resultant hydrogen halide is run in preferably in the form of an aqueous solution of an alkali hydroxide or carbonate or acetate or borate. The liberated acid can also be disposed of by means of a buffer, such for example as sodium bicarbonate. The dyestuff which is produced is precipitated from the solution by salting out or by the addition of an acid it necessary with the aid of heat and after preliminary distillation of the organic solvent. The precipitated dyestuff which has a distinct alkaline reaction, there is added at 15 and in the course of 4-5 hours, a 10% benzene solution of 2 methylbutadiene 1,4 dicarboxylic acid chloride until free amino group can no longer be detected in the condensation mass. The thus-produced disazo dyestuif is isolated and dried. It corresponds to the is then isolated by filtration and, if necessary, after conversion into an alkali salt, is dried;

If groups which are capable of metal complex formation are introduced by the aminoazo compounds or in the building up of the dyestufi, the end products can be 5 converted into metal complex compounds in substance or on the fiber by treatment with metal-yielding agent. formula so3H- -N=No-oont H:GC--C-N=N sogn HO()\ /N N\ -OH COOH NO-NELCO-CH=E-OH=CHOC.HNON HOOO/ The metal complex compounds generally possess enhanced fastness to light and improved fastness to wet treatments, as compared with the unmetallized dyestuffs. Here again the preferred metals are copper and nickel.

The following examples illustrate the invention without limiting the same. In such examples the parts are parts by weight, the percentages are percentages by weight and the temperatures are given in degrees centigrade.

EXAMPLE 3 34 parts of the aminomonoazo compound, prepared by coupling diazotized l-carboxy-2-aminobenzene-S-sul fonic acid with l-(4-amino-1',1"-stilbenyl4')-3-meth yl-5-pyrazolone-2,2"-disulfonic acid, are dissolved neutral in 1000 parts of hot water, and then are converted into the copper complex compound by the addition of 62 parts of a 20% aqueous copper sulfate solution in the presence of aqueous sodium acetate. The dyestuif solution is then rendered alkaline by the addition of excess sodium bicarbonate and is cooled with ice to 10-l5. At the latter temperature there is added to the dyestuff solution, in the course of 2-3 hours and while stirring very thoroughly, a 10% solution of 1,4-dichlor0butadiene-1,4- dicarboxylic acid chloride in chlorobenzene until free amino group can no longer be detected. The thus-formed disazo dyestuff isafter being isolated, dried and ground--a brown powder which corresponds to the 0 The term soda refers to sodium carbonate.

EXAMPLE 1 46.4 parts of the aminoazo compound, prepared by coupling diazotized Z-aminonaphthalenel,8-clisulfonic 30 acid with 1-amino-3-acetylaminobenzene, are dissolved neutral in water at room temperature (e. g. 20-30") with the addition of aqueous sodium hydroxide solution. Into the resultant solution, there is slowly added dropwise, and while stirring very thoroughly, a 10% benzene solution of butadiene-1,4-dicarboxylic acid chloride until the presence of free amino group can no longer be detected in the condensation mass. During this operation, the reaction solution is maintained constantly weakly alkaline by running in a 10% aqueous sodium carbonate solution. The thus-formed disazo dyestuff is precipitated at 80 with the aid of sodium chloride, formula N:- fi-CCH5 HOaS- (I%O CuOC\ NQoH=oH--NH.oo o=oH- 802E SOsH after which it is filtered and dried. It corresponds to the formula and dissolves with yellow coloration in water and concentrated sulfuric acid. Its dyeings on cotton and fibers of regenerated cellulose are of excellent fastness to light and to wet treatments.

The same disazo dyestufi is obtained when, while otherwise proceeding as described in the foregoing paragraph, the aminomonoazo compound of the example is first condensed with 1,4-dichlorobutadiene-1,4-dicarboxylic acid chloride, and the copper complex compound only thereafter prepared from the condensation product.

The following table sets forth additional disazo and polyazo dyestuifs which can be prepared after the manner described in the foregoing examples and which are suitable for use in the dyeing of cotton and fibers of regen' erated cellulose. To characterize the said disazo and polyazo dyestuifs, columns I and II list the two aminoazo compounds which are bound together by means of the butadiene-1,4-dicarboxylic acid halide. Column 111 indicates the type of resultant dyestuif and column IV sets forth the shade of the dyeings obtained therewith; where metallizable disazo and polyazo dyestuffs are involved the shade is of dyeings obtained with the coppered product.

NHCOCH:

and is a yellow-brown powder which dissolves with yellow coloration in water and with scarlet-red coloration in concentrated sulfuric acid. It dyes cotton and fibers of regenerated cellulose in clear yellow shades of very good dischargeability and fastncss to light.

D EXAll L LE 2 334,053 :7 g The formula of representative dyestuffs of the aforesaid while stirring thoroughly, until no free amino group can table are asfollows: be detected. The condensation mass is then heated to EXAMPLE 8 [H|s--N=N@-N=N--Nn. o 0-0 H=CH 80311 (SH: J2

EXAMPLE 17 30:11 3-NH. o C-ON=NO-NH.C 0-o 13:0 11-- nood 0H 313; .i2

EXAMPLE 70430", and the reaction product isolated therefrom and dried. NH.CO-CH=OH- 20 EXAMPLE 34 84.8 parts of 2-hydroxy-3,5-dicarboXy-4-amino-1,1- SO3H diphenylurea-S-sulfonic acid are diazotized and gradually l (FOR I added to a solution of 58 parts of butadiene-1,4-dicar- HO boxylic acid-[S-hydroXy-7-sulfonaphthyl-(2)l-amide in 1500 parts of Water, 500 parts of pyridine and 100 parts l H 2 of aqueous ammonia of 25% strength. The coupling is 3 EXAMPLE 33 over in about 12 hours and the resultant diasazo dyestuff is salted out, filtered and dried. It corresponds to the 58 parts of symmetrical butadiene-1,4-dicarboxylic formula SlOaH H03s- NH.C o-on=on Q-NILC 0.1m N=N- l HO 0d on do on no 2 acid-[5-hydroxy-7-sulfonaphthyl-(2) J-arnide, in the form and dyes cotton fibers of regenerated cellulose in the afterof the disodium salt, are dissolved in 800 parts of warm coppering process in bordeaux-red shades of very good water. 60 parts of crystalline sodium acetate are added f t tglight d towashing, to the solution, is then cooled to 0-5 There is For conversion thgreof intQ the copper complex comthen added to the resultant solution, while stirring thorpound 140 parts f the dyesmfi are dissolved at 0435 l ys Q e-3 halo suspenslon obtamed by the f in 3000 parts of Water and parts of crystalline sodium f' dlazouzanofl of 72 Parts of acetate and parts of concentrated acetic acid are then i !2225511 2333 $g gg t gg sggfig zgg gggg i g added to the solution. Thereupon a solution of 50 parts V r then neutralized by the dropwise addition of an aqueous 50 f ?i fif f g mtzoo Wate? g sodium b1carbonate solution over a period of 4-5 hours n g a er emPcra me Is mamtame until a brilliant yellow alkaline reaction is achieved, for an hour at The r5u1t'am 9 complex whereupon after the Coupling has ended, the obtained compound separates as the sodium salt, and 1S filtered and solution is heated to approximately the produced dried. It is a dark powder which dyes cotton and fibers disazo dyestufi' salted out, filtered OE and dried. It cor- 55 0f fegencmied mini-11056 in boi'deaux'l'ed Shades of y responds to the formula good fastness to light and of good fastness to washing.

S0311 H038 NH.G00H=CH 1 Hood OH H0 2 and is a dark powder which dissolves with red coloration G5 The fastness to wet treatments is improved by aftertreatin water and which dyes cotton and fibers of regenerated ment on the fiber with copper salts.

cellulose in red shades. The dyeings possess good fast- EXAMPLE 35 ness properties; these properties can be somewhat improved by aftertreatrnent with o i ldi agent5 19.5 parts of the diamine, obtained by the condensation In order to prepare the symmetrical b t di 1,4.di H of two mols of Z-nitro-S-aminobenzene-l-carboxylic acid carboxylic acid-[S-hydrexyJ-sulfonaphthyl-(2)] amidg with one mol of butadiene-1,4-dicarboxylic acid chloride 239 parts of Z-amino-S-hydroxynaphthalene-7-sulfonic P reduciiofl of the F 8 f the amino group, are acid and 40 parts f Crystalline Sodium acetate are di dlSSOlVtZCl 1n water with the addition of aqueous sodium solved in 2000'parts of Water. Thereupon a 10% solution hydroxide solution, after which 6.9 parts of sodium nitrite of butadiene-1,4.-dicarboxylic acid chloride in benzene is a are added. The solution is slowly introduced into a mixadded to the solution, in the course of 3-4 hours and ture of 4-0 parts of 30% hydrochloric acid and parts and dyes cotton and fibers of regenerated cellulose in blue 2,784,063 I t 9 1o of ice, in such manner that the final temperature of the acid coupling of 800 parts of diazotized 4-nitro-4'-aminomixture is between and 10. Upon completion of the l,1-stilbene-2,2-disulfonic acid with ,274 parts of lensuing tetrazotization, the suspension of the precipitated amino-Z-methoxy-S-methylbcnzene, are .diazotized and tetrazo compound is run, in the course of 30 minutes, into then coupled with a soda-alkaline solution of 584 parts an alkaline solution of. 25 .4 parts of 1-phenyl-3-methyl-5- 5 of butadiene-1,4-dicarboxylic acid-[5-hydroxy-7-sulfopyrazolone-4'-sulfonic acid. The reaction of themass is naphthyl-(2)]-amide. The resultant tetrakisazo dyestutf maintained constantly alkaline by the addition of sodium is salted out and filtered. Its copper complex compound carbonate in small portions. Coupling takes place corresponds to the formula I i OCu o H I S0311 8 03 (3113 11033 NH.CO-CH=CH-J2 rapidly; after about 2 hours the solution containing the and dyes cotton and fibers of regenerated cellulose in formed disazo dyestuit is heated to 70, and the dyestuff greenish gray shades of good fastness to light and washsalted out therefrom, filtered and dried. It corresponds to lug. Its fastness to wet treatments is improved by aftertreatment on the fiber-with copper salts.

the formula V '1 I EXAMPLE 38 TE 21; parts of butadiene-l,4-dicarboxylic acid-[4-aceto- N ("J-0H acetylamino-2',2-disulfo-l,l"-stilbenyl-(4')l-amide are G OOOH dissolved in 1000 parts of water with the aid of an excess 2 of sodium carbonate, and then coupled at 02 with a 25 diazo solution prepared from 5.6 parts of Z-amino'benzene-l-carboxylic acid. The formed disazo dyestufi is and is an orange-yellow powder which dissolves with yelprecipitated, filtered and dried. It is a yellow powder low coloration in concentrated sulfuric acid and in water. which corresponds to the formula N=N--C--C 0 .NH-C CH=OHONH.C O-OH=CH 'no-i i v l J I SOaH I 80311 00011 CH5 3 Its coppered dyeings on cellulose fibers are yellowish and dissolves with yellow coloration in concentrated sulorange; dyeings of the same shade are obtained with the furic acid. Its coppered dyeings on cellulose fibers are copper complex compound prepared in substance. The greenish yellow and possess very good fastness to wet dyeings are characterized by excellent fastness to light and treatments and to light. good fastness to wet treatments. EXAMPLE V39 EXAMPLE 36 33 parts of butadiene-l,4-dicarboxylic acid-[3"-sulfo- 24.4 parts of 4,4-diamino-3,3-dimethoxy-1,1'-diphenyl 4"-amino-1,l"-diphenyl-(4)l-amide, in the form of the are tetrazotized and coupled with a solution of 30.4 parts disodium salt, are dissolved in 400 parts of water. T0 of l-hydroxynaphthalene-3,8-disulfonic acid at 0 in a the resultant solution, there are then added 6.9 parts of medium rendered alkaline with sodium carbonate. The sodium nitrite and a's'ufficient quantity of ice to bring resultant diazoazo compound is separated by filtration the temperature of the mass down to 5. At this temand, after the addition of pyridine, is further coupled with perature and in the course of 20-30 minutes, 80 parts a solution of the copper complex compound of the inof 15% hydrochloric acid are then added dropwise. The termediate obtained by the soda-alkaline coupling of 22.3 thus-acidified tetrazo suspension is stirred for about 3 parts of diazotized l-hydroxy-2-amino-6-chlorebenzenelhours at 5, after which excess nitrous acid is decomsulfonic acid with 58 parts of butadiene-1,4-dicarboxylic posed by means of urea or aminosulfonic acid, and the acid-[5-hydroxy-7-sulfonaphthyl-(2)l-amide. The thussuspension then slowly added to an ice-cold solution of formed dyestuff is precipitated from the solution by means 25 parts of 1-acetoacetylamino-4-hydroxybenzene-3-carof sodium chloride, is separated by filtration and is subboxylic acid and 500 parts of water, the last-named solujected todemethylating coppering. The resultant 'coppertion containing an excess of sodium carbonate. Upon containing dyestuft corresponds to the formula completion of the ensuing coupling the reaction mass is Hots 0-Cu--O oon 0. O-Cu 0 c heated to -80", after which the resultant disazo dyestufi'is isolated. Dried and ground, it is an olive-brown powder which corresponds to. the formula shades'of very good fastness to light and of good fastness 65 -0H 7 H0O 303B 7 (1H: to washing. The fastness to wet treatments is improved and dissolves with yellow coloration in water. Its dyeaftertieatmint 9 t fi Wlth P F l v H ings on cotton and fibers of regenerated cellulose, treated EXAMPLE 37 with copper-yielding agents, are yellow and have good 1096 parts of the aminoazo compound, obtained by the fastness properties.

1 1 EXAMPLE 40 46 parts of 1-carboxy-Z-aminobenzene-S-sulf0nic acidmethylamide are diazotized and coupled in soda-alkaline solution with 104 parts of the dipyrazolone of the formula which can be prepared in a manner analogous to that set forth in the second paragraph of Example 33. Upon completion of the coupling, the reaction mass is heated and, after the addition of a small quantity of sodium chloride is boiled until the dyestuff pulp has been converted into a readily filterable precipitate. The latter is filtered hot, and is then dried.

To convert the disazo dyestufif into the nickel complex compound, 50 parts of the disazo dyestuff are dissolved in 2000 parts of Water. To the resultant solution, there are first added 30 parts of crystalline sodium acetate and then, at about 70 and in the course of -30 minutes, a 10% aqueous nickel sulfate solution until a permanent excess of nickel(II)-ions can be detected. The formed nickel complex compound which corresponds to the formula is precipitated from the solution by the addition of sodium chloride and is then filtered and dried. It dyes cotton and fibers of regenerated cellulose in yellow shades of good fastness to light and to wet treatments.

EXAMPLE 41 79 parts of the amino intermediate obtained by the condensation of 0.095 mol of Z-arnino-S-hydroxynaphthalene-7-sulfonic acid and 0.105 mol of 4-nitro-4-aminol,1-stilbene-2,2'-disulfonic acid with 0.105 mol of butadiene-l,4-dicarboxylic acid chloride and reduction of the nitro group to the amino group, are dissolved in 300 parts of water with the addition of sodium carbonate and then coupled in soda-alkaline solution with 22.3 parts of diazotized 1-hydroxy-Z-amino-6-chlorobenzene-4-sulfonic acid, to form the monoazo dyestuff. The latter is salted out with sodium chloride and filtered. For diazotization thereof, 101 parts of the obtained aminoazo compound are dissolved in 300 parts of water, 7 parts of sodium nitrite are added to the solution, and the latter adjusted to a mineral acid reaction by the addition of 70 parts of hydrochloric acid at 1015 while stirring thoroughly. The resultant suspension of the diazoazo compound is then gradually added to an aqueous solution of 1.7.4 parts of 1-phenyl-3-methyl-5-pyrazolone, said solution containing sodium hydroxide. The formed disazo dyestutf is salted out, filtered and, after reprecipitation from water and re-filtering, dried. It is a dark powder which corresponds to the formula SOZH ('31 on at) and dyes cotton and fibers of regenerated cellulose by the after coppering process in red shades of very good fastness to light and good fastness to washing.

12 EXAMPLE 42 100 parts of cotton are entered at into a dyebath containing a solution of 1 part of anhydrous sodium carbonate, 0.5 part of the dyestuff obtained according to Example 1 and 2000 parts of water. The dyebath is slowly heated to boiling and then, after the addition of 20 parts of anhydrous sodium sulfate, is allowed to cool slowly to 70. The dyed material is withdrawn, washed with cold Water and dried. There is obtained a yellow dyeing of excellent fastness to light and of excellent dischargeability.

EXAMPLE 43 2 parts of the dyestuff described in Example 2 and 30 parts of sodium sulfate are dissolved in 3000 parts of water at 40-50. parts of cotton are then entered into the thus-prepared dyebath. The bath is heated to boiling in the course of A: hour, maintained at this tem perature for A hour and then allowed to cool for' /t hour. The dyed cotton is Withdrawn and thoroughly rinsed.

For aftercoppering, the dyed material is moved about for /2 hour at 70 in a solution of 2 parts of crystalline copper sulfate, 2 parts of concentrated acetic acid and 3000 parts of water. The material is then again rinsed and finally dried.

--NH.CO-CH=CH- EXAMPLE 44 2 parts of the copper complex compound obtained according to Example 3, first paragraph, areused for dyeing cotton after the manner described in the first paragraph of Example 43. The dyeing is characterized by excellent fastness to light and to wet treatments.

EXAMPLE 45 A printing paste consisting of 20 parts of the disazo dyestufi of Example 1, 305 parts of hot water, 500 parts of a thickening agent (for example gum tragacanth 6%), 100 parts of urea, 40 parts of thiodiethyleneglycol, 10 parts of an anion-active Wetting agent, 15 parts of disodium phosphate and 10 parts of crystalline sodium chlorate is used for printing on viscose fabric. The print is dried, steamed for 1 hour at 100-102, then rinsed with cold water, and dried.

Having thus disclosed the invention, what is claimed 1s:

1. A water-soluble azo dyestufl which corresponds to the formula wherein each of R1NH- and RzNH- is the radical of an aminoazo compound selected from the group consisting of aminoazo compounds of the benzene, naphthalene, pyrene, pyrazolone and acetoacetylamide SOBH SOaH series, containing from one to three azo groups, one to four water-solubilizing groups, and zero to two metal atoms selected from the group consisting of copper and 13 a nickel atoms, each said metal atom being present in the dyestuff molecule in the form of a complex linkage, -,-z-- being a member selected from the group consisting of and Me representing the aforesaid metal atom, and wherein x is a member selected from the class consisting of hydrogen and chlorine, and y is a member selected from the class consisting of hydrogen and lower alkyl.

2. An azo dyestufi which corresponds to the formula son; NHCOC z 0111 '7 V A I 2 3. An azo dyestuff which corresponds to the formula 4. An azo dyestufi which corresponds to the formula 7, A processofpreparation of dis'- and polyazo dyestuffs comprising the steps of condensing, in an aqueous medium and inthe presence of an acid binding agent, (a) two mols of aminoazo-compound selected from the group consisting of aminoazo compounds, of the benzene, naphthalene, pyrene, pyrazolone and acetoacetylamide series, containing from one to three azo groups, one to afour water-solubilizing groups, and zero to two metal atoms selected from the groupconsisting of copper and nickel atoms and (b) two mols of a mixture of two to three of said aminoazo compounds which are different fromeach other, with ,(c) zonermol of a dicarboxylic acid halide which corresponds to the formula 4 I wherein x is a member selected from the class consisting of hydrogen and chlorine, and y is a member selected from the class consisting of hydrogen and lower alykyl, each metal being present in said aminoazo compounds in the form of a complex linkage, -zbeing a member selected from the group consisting of v a p a -0- and o-oand Me representing the metal atom.

8. The process of preparation of a disazo dyestuff [HOaS-O-N: QN=N N 0-011- 03 01H H, .12

5. An azo dyestufi which corresponds to the formula 9101.0 cOmmQnnc o-o H=OH- 1100 H H. J2

6. An azo dyestufi which corresponds to the formula 0 all 2 comprising the step of condensing, in an aqueous medium and in the presence of an acid binding agent, 2 mols of with 1 mol butadiene-l,4-dicarboxy1ic acid chloride.

9. The process of preparation of a disazo dyestutf 15 comprising the step of condensing, in an aqueous medium and in the presence of an acid binding agent, 2 mols of the aminoazo compound Which corresponds to the formula with 1 mol 1,4-dich1orobutadiene-1,4-dicarboxylic acid chloride.

10. The process of preparation of a tetrakisazo dyestuff comprising the step of condensing, in an aqueous medium and in the presence of an acid binding agent, 2 mols of the aminazo compound which corresponds to the formula with 1 mol butadienc-1,4-dicarboxy1ic acid chloride.

12. The process of preparation of a disazo dyestuff comprising the step of condensing, in an aqueous medium and in the presence of an acid binding agent, 2 mols of' the aminoazo compound which corresponds to the formula 11. The process of preparation of a disazo dyestufi? 25 with 1 mol butadiene-l,4-dicarboxylic acid chloride.

comprising the step of. condensing, in an aqueous medium and in the presence of an acid binding agent, 2 mols of the aminoazo compound which corresponds to the formula SOQH References Cited in the file of this patent UNITED STATES PATENTS Markham. 

1. A WATER-SOLUBLE AZO DYESTUFF WHICH CORRESPONDS TO THE FORMULA 